The Welfare Party participated in the 1991 elections in a triple alliance with the Nationalist Movement Party (MHP) and the Reformist Democracy Party (IDP). They gained 16.9% of the vote. They won 62 deputies to parliament, but 19 ones of MHP (with founding Democratic Movement Party in 25 December 1991 and joining the MÇP in 29 December 1991) and 3 ones of IDP left the Welfare Party after it. Their popular vote increased over the years until they became the largest party under Prime Minister Necmettin Erbakan in 1996. The coalition government of Erbakan was forced out of power by the Turkish military in 1997, due to being suspected of having an Islamist agenda.[1]

After the closure of the party, the Treasury demanded the return of grands worth around one trillion lira, i.e. one million in today's currency (around € 477,000). Party officials stated that the funds were spent on party activities. However, an investigation revealed that the official documents were forged.[5][6][7]

In the beginning of 1999, Necmettin Erbakan and 78 party officials stood trial in Ankara for embezzlement charges. The case became known as the "Lost Trillion Case" or the "Missing Trillion Case" (Turkish: Kayıp Trilyon Davası).[5][6][7] In March 2002, the court sentenced Erbakan to two years and four months in prison. 68 party officials received sentences of up to one year and two months in prison. The sentences were approved by the Supreme Court of Appeals.[8][9] The European Court of Human Rights upheld the ban as well.[10]